LG LSS-3200A Service Manual page 10

SOFTWARE CORRUPTION PROBLEM
ELECTRICAL TROUBLESHOOTING GUIDE
1. POWER(SMPS) CIRCUIT
2. AUDIO CIRCUIT
1) NO ATSC AUDIO..................................................................................................................................3-7
2) NO DIRECTV AUDIO .........................................................................................................................3-11
3) NO NTSC AUDIO ...............................................................................................................................3-12
4) NO SPDIF OUT FOR ATSC & DIRECTV ..........................................................................................3-13
5) NO SPDIF FOR NTSC .......................................................................................................................3-14
6) NO 3/ 4 RF AUDIO .............................................................................................................................3-15
3. DIRECTV FRONT- END CIRCUIT(QPSK)
4. DVI CIRCUIT
........................................................................................................................................3-19
5. CPU(SYSTEM CONTROL) CIRCUIT
6. VIDEO CIRCUIT
7. DIRECTV TP- DEMUX /MODEM CIRCUIT
8. DIRECTV TP- DEMUX /MODEM CIRCUIT
9. ATSC/ QAM FRONT- END CIRCUIT
10. NTSC FRONT- END CIRCUIT
11. FRONT PANEL CIRCUIT
12. CAM BOARD CIRCUIT
OVERALL BLOCK DIAGRAM
1. OVERALL BLOCK DIAGRAM 1 ............................................................................................................3-47
2. OVERALL BLOCK DIAGRAM 2 ............................................................................................................3-49
BLOCK DIAGRAM & SIGNAL FLOW
1. POWER(SMPS) BLOCK DIAGRAM ......................................................................................................3-51
2. DIRECTV BLOCK DIAGRAM & SIGNAL FLOW...................................................................................3-53
3. ATSC BLOCK DIAGRAM & SIGNAL FLOW .........................................................................................3-55
4. NTSC BLOCK DIAGRAM & SIGNAL FLOW.........................................................................................3-57
CIRCUIT DIAGRAM
......................................................................................................................................3-59
1. POWER(SMPS) CIRCUIT DIAGRAM ....................................................................................................3-59
2. CPU(PPC405CR) CIRCUIT DIAGRAM ..................................................................................................3-61
3. CPU PERI, RF-REMOTE, VCR-CTRL CIRCUIT DIAGRAM..................................................................3-63
4. FRONTEND CIRCUIT DIAGRAM...........................................................................................................3-65
5. HD2 & SDRAM CIRCUIT DIAGRAM .....................................................................................................3-67
6. DIRECTV HD-STB CIRCUIT DIAGRAM ................................................................................................3-69
7. VDP I/F & DISPLAY OUTPUT CIRCUIT DIAGRAM ..............................................................................3-71
8. NTSC AUDIO PROCESSOR CIRCUIT DIAGRAM ................................................................................3-73
9. DIRECTV TP DEMUX & CAS I/F CIRCUIT DIAGRAM .........................................................................3-75
10. 2400 BPS ISO MODEM CIRCUIT DIAGRAM ......................................................................................3-77
11. POWER REGULATION CIRCUIT DIAGRAM.......................................................................................3-79
12. CAM I/F CIRCUIT DIAGRAM ...............................................................................................................3-81
13. FRONT (2R, VFD, KEY-SCAN) CIRCUIT DIAGRAM ..........................................................................3-83
14. FRONT POWER KEY CIRCUIT DIAGRAM .........................................................................................3-85
PRINTED CIRCUIT DIAGRAMS
1. DIGITAL MAIN P.C.BOARD(BOTTOM)..................................................................................................3-87
2. DIGITAL MAIN P.C.BOARD(TOP)..........................................................................................................3-89
3. CAM P.C.BOAR(BOTTOM) ....................................................................................................................3-91
4. CAM P.C.BOAR(TOP) ............................................................................................................................3-92
5. POWER P.C.BOARD ..............................................................................................................................3-91
6. TIMER P.C.BOARD.................................................................................................................................3-93
7. KEY P.C.BOARD ....................................................................................................................................3-95
SECTION 3
ELECTRICAL
CONTENTS
.....................................................................................................3-2
....................................................................................................................3-5
....................................................................................................................................3-7
...............................................................................................3-21
...................................................................................................................................3-29
................................................................................................3-41
........................................................................................................3-43
.................................................................................................................3-44
....................................................................................................................3-46
....................................................................................................................3-47
.......................................................................................................3-51
................................................................................................................3-87
............................................................................................3-5
......................................................................................3-16
.....................................................................................3-37
.....................................................................................3-39
3-1